1. Field of the Invention
The present invention relates to a battery charging system, and in particular to a battery charging system by which a user can enjoy particular functions of an electric appliance while charging it
2. Description of the Conventional Art
Generally, there were well-known various chargers being used for a potable cassette tape player, a cellular phone, etc. However, because each of these chargers is designed only to perform its charging function, a user can not enjoy a particular function of the electric appliance when charging it by attaching it into the charger.
For example, in the case of a cassette tape player or a cellular phone which trend to be compact and light, it should have its own charger corresponding thereto, respectively, of a user want to enjoy its function, he must directly connect an ear phone or an external speaker to it, thereby causing much inconvenience and additionally requiring an external apparatus.
A technique for installing a speaker in the interior of the electric appliance has been disclosed in order to overcome the above-described problems. However, this method is not proper for state-of-the-art portable systems which trend to be more compact and lighter.
There was disclosed a conventional audio system capable of performing a cassette tape player's function while charging a cassette tape player being equipped detachably with it, in which the audio system comprises a speaker and a charging apparatus therein.
Now, the construction and operation of a charging apparatus for a cassette tape player of the above audio system will be explained with reference to FIG. 1.
As shown in FIG. 1, an input terminal IN of an amplifier circuit unit 3 is connected with an output terminal OUT of a cassette tape player and radio circuit unit 1 through connection terminals C1.fwdarw.C1' and C2.fwdarw.C2'. A charging battery 2 is connected with an electric power input terminal VCC of the cassette tape player or radio circuit unit 1 through a switch S1 and is connected with a rectifying circuit unit 4 through connection terminals C3 and C3'. A charging battery 2 is connected with a charging circuit unit 5 through connection terminals C4 and C4'. In the drawings, reference numeral AC represents an alternating current.
In the above circuit, when the charging battery 2 disposed in the cassette player or radio receiver A is fully discharged, the cassette tape player or radio receiver A is engaged with a main body B of the receiver. The connection terminals C1 and C2 of the output terminal OUT of the cassette tape player or radio circuit unit 1 are connected with the connection terminals C1 and C2' of the input terminal IN of the amplifier circuit unit 3, and the connection terminal C3 of the electric power terminal Vcc of the cassette tape player or radio circuit unit 1 is connected with the connection terminal C3' of the output terminal of the rectifying circuit unit 4. Thus, the alternating current (AC) flows through the rectifying circuit unit 4, thereby driving the cassette tape player or radio circuit unit 1. Therefore, the signal of the output terminal OUT is applied to the amplifier circuit unit 3 through the connection terminals C1.fwdarw.C1' and C2.fwdarw.C2', so that the signal is amplified, thereby outputting sound through the speakers.
In addition, when the cassette tape player or radio receiver A is engaged with the main body B of the receiver, since the switch S1 is off, the alternating current AC is applied to the charging battery 2 through the charging circuit unit 5 and the connection terminals C4 and C4', thereby implementing a charging operation. When the cassette tape player or radio receiver A is separated from the main body B of the receiver, the switch S1 is on, and the connection terminals C1.fwdarw.C1', C2.fwdarw.C2', C3.fwdarw.C3' and C4.fwdarw.C4' are disconnected, so that the charged voltage in the charging battery 2 is applied to the cassette tape player and radio receiver 1, thereby implementing a normal operation.
In the conventional charging apparatus of the audio system with which a cassette tape player is equipped detachably, it is possible to output sound of the cassette tape player through the speaker of an audio system, while charging. However, in this case, the cassette tape player requires its own audio system and charging apparatus, thereby having no compatibility with other types of cassette tape players. In addition, the conventional charging apparatus is not its functions capable of being selected and controlled by a user.